Scientific American Supplement, No. 415, December 15, 1883 eBook

The bruised leaves applied directly usually prove
sufficient for the purpose; as to whether it will
prove sufficiently valuable to add to our list of
pharmaceutical preparations will require longer and
more extended experiment.—­New Remedies.

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DANGER FROM FLIES.

Dr. Grassi is said (British Medical Journal)
to have made an important, and by no means pleasant,
discovery in regard to flies. It was always recognized
that these insects might carry the germs of infection
on their wings or feet, but it was not known that they
are capable of taking in at the mouth such objects
as the ova of various worms, and of discharging them
again unchanged in their faeces. This point has
now been established, and several striking experiments
illustrate it. Dr. Grassi exposed in his laboratory
a plate containing a great number of the eggs of a
human parasite, the Tricocephalus dispar.
Some sheets of white paper were placed in the kitchen,
which stands about ten meters from the laboratory.
After some hours, the usual little spots produced
by the faeces of flies were found on the paper.
These spots, when examined by the microscope, were
found to contain some of the eggs of the tricocephalus.
Some of the flies themselves were then caught, and
their intestines presented large numbers of the ova.
Similar experiments with the ova of the Oxyuris
vermicularis and of the Toenia solium afforded
corresponding results. Shortly after the flies
had some mouldy cream, the Oidium lactis was
found in their faeces. Dr. Grassi mentions an
innocuous and yet conclusive experiment that every
one can try. Sprinkle a little lycopodium on sweetened
water, and afterward examine the faeces and intestines
of the flies; numerous spores will be found.
As flies are by no means particular in choosing either
a place to feed or a place to defecate, often selecting
meat or food for the purpose, a somewhat alarming
vision of possible consequences is raised.

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THE ZOOLOGICAL SOCIETY’S GARDENS.

The erection of the new house for the accommodation
of the serpents, alligators, and other reptiles, which
is shown in our illustration, must be commended as
a valuable improvement of the Zoological Society’s
establishment in Regent’s Park. This building,
which has a rather stately aspect and is of imposing
dimensions, constructed of brick and terracotta, with
a roof of glass and iron, stands close to the south
gate of the Gardens, entered from the Broad Walk of
the Park. The visitor, on entering by that gate,
should turn immediately to the left hand, along the
narrow path beside the aviary of the Chinese golden
pheasants, and will presently come to the Reptile House,
which is too much concealed from view by some of the
sheds for the deer. The spacious interior, represented